The present invention relates to electric door locking and releasing systems, which comprise electromechanical strikes installed in the doorjamb, providing adaptable comprehensive door locking and releasing functions. It is applicable for use with most door locks and to a wide variety of combinations of dead bolts and latch bolts.
Most main entry doors consist of two types of bolts, a dead bolt and a latch bolt. These two types of bolts provide different and necessary functions that together enable the normal operation of a modem main entry door. The latch bolt latches and holds the door in a closed position. It enables the user to push or swing the door closed and latched, and positions it for the dead bolt operation. The dead bolt, when locked, provides a secure and tamper resistant locking function. The functions of these bolts are accomplished as follows:
Dead bolts usually have two detent positions, the locked position in which the dead bolt is extended out of the mortise in the door, and the unlocked position in which the dead bolt is retracted into the mortise.
There are two main kinds of latch bolts, the simple latch bolt and the complex latch bolt (the complex latch bolt is also known in the art as the dead latch bolt.) Latch bolts usually extend out of the door by a spring in the mortise. The simple latch bolt is an angular tongue-like bolt that operates against a spring in the mortise. The complex latch bolt is a similar angular tongue-like bolt that operates against a spring but also comprises a disabler element, collateral to the tongue-like bolt that operates against a second spring in the mortise. When the disabler element of the complex latch bolt is pushed into the mortise while the latch bolt is extended out of the mortise, the latch bolt is locked in its extended position and cannot be pushed into the mortise. This provides secure and tamper resistant functionality to the complex latch bolt, overcoming a shortcoming of the simple latch bolt. This feature of the complex latch bolt prevents a potential intruder from opening the latch bolt by sliding a thin card such as a credit card between the door end and the doorjamb.
The present invention, in contrast to prior art, operates with all conventional dead bolts and latch bolts, in any combination. The present invention enables operation with the two types of latch bolts, the simple latch bolt and the complex latch bolt, employing the same mechanism. The present invention can also operate the latch bolt independently, whether or not the dead bolt is extended out of the mortise.
Providing integrated solutions to all types of bolts is necessary for a comprehensive adaptable electromechanical strike locking system to be useful. Prior art adaptable electromechanical strike locking systems do not control the releasing and locking of strikes for both latch bolts and dead bolts in a single system since different strikes would be necessary for each type of bolt and different controllers would be necessary for each type of strike. It is cumbersome for a user to operate more than one controller to open an electromechanical strike locking systems. The present invention simplifies the control of the electromechanical strike locking system by providing a universal strike for both the dead bolt and the latch bolt and a single controller. Prior art electromechanical strike locking systems have not addressed integrated fault tolerant mechanisms. A fault tolerant system, operating both the dead bolt and the latch bolt, is necessary for locking systems to operate reliably and provide confidence to the user of reliability. These deficiencies in the prior art may have hindered the wide acceptance of this technology, as users require dependable operation under any conditions. There is a need for a complete integrated system that addresses the need for better functionality and flexibility of electromechanical strikes and the compatibility with a wide variety of door lock configurations as addressed by the present invention.
Prior art electromechanical strike locking systems have not gained widespread acceptance and use because of deficiencies in reliability, the lack of fault tolerance capability, and the inability to operate them with an assortment of preinstalled locks in various configurations. Prior art electromechanical strike locking systems are difficult to install and operate because they lack the universality of the present invention, i.e., one type of strike for both the latch bolts and the dead bolts, and the ability to employ the same strike for left and right doorjambs.
These deficiencies in prior art electromechanical strike locking systems are not an issue in exclusive electromechanical strike locking systems, which have gained wide acceptance in business and industrial applications. An exclusive electromechanical strike locking system is a self-contained locking system, i.e., the mortise in the door and the electromechanical strike are installed together as one operable unit, which does not allow for interoperability with other existing locking systems. An example of one exclusive electromechanical strike locking system is the SDC series 50 manufactured by Security Door Controls of Westlake Calif. The system does not allow for interoperability with other locking systems and, therefore, is an exclusive electromechanical strike locking system. The present invention, in contrast, is an adaptable and comprehensive electromechanical strike locking system that works with a variety of existing locks by requiring only the retrofitting of the strikes in the doorjamb.
U.S. Pat. No. 4,017,107 by Hanchett, dated Apr. 12, 1977 (hereinafter Hanchett 107) provides a strike frame for receiving a dead bolt or a latch bolt and to allow the bolts to move through a notch in the doorjamb. Hanchett 107 teaches the use of a rotary pivoting shutter as a lock system. The system operates by means of a vertical rotary motion that opens and closes the strike.
The present invention solves the deficiency encountered by the vertical rotary operation, in particular the operation with the latch bolts. The design of a latch bolt requires that it be pushed transversely upon a lipped plate to lock and latch the door. The contouring of the latch bolt tongue makes the vertical rotary motion of that type of strike unworkable. Also, the rotary motion of the shutter defeats the operation of the disabler of the complex latch bolt.
The improvements of the present invention for the locking and releasing of bolts are achieved by the use of linear horizontal movement of the strike. The linear horizontal motion of the strike enables controlling the motion contour of the strike in both directions, the distance of the motion and the calibration of the travel distance.
The present invention enables the use of locking mechanisms that can work with most sizes and combinations of dead bolts and latch bolts (both simple and complex latch bolts), and provides a complete and integrated system.
U.S. Pat. 5,100,186 by Nordvall, dated Mar. 31, 1992 (hereinafter Nordvall 186) teaches the employment of a linear vertical motion of a slide within a strike in the doorframe. The vertical motion of the slide presents limitations for the operation of the latch bolt, in particular for the transverse movement of the latch bolts tongue against the strike. In addition the fixed size of the recess in the strike is not adjustable to receive different sizes of dead bolts, and the strike is not reversible, thus, requires the use of left-right systems. The system in Nordvall 186 also does not provide a fault tolerant method employing closed loop control. In contrast, the present invention is universal to all left-right, inside-outside doors. It permits the control of the speed of the strike, the user can calibrate the travel distance of the strike, and it enables the use of a fault tolerant operation employing closed loop control. Further, the present invention, due to its horizontal motion, also operates with all types of latch bolts, thus, lending itself to a comprehensive lock system.
The present invention enables, for the first time, an adaptable and comprehensive electromechanical strike locking system, operating on both the dead bolt and the latch bolt, which allows the user to independently operate the door either by using the conventional door access system or the electromechanical strike locking system.